Method for producing webs including polypropylene fibers



United States Patent 3,377,181 METHOD FOR PRODUCING WEBS INCLUDING POLYPROPYLENE FIBERS Tsutomu Karnijo and Takehiko Fujimoto, Higashiyamaku, Kyoto-slit, and Toshio Saiuchi, Yasu-gun, Shigaken, Japan, 'assignors to Toyo Rayon Kabushiki Kaisha, Tokyo, Japan, and Sanyo Kasei Kogyo Kabushiki Kaislia, Kyoto-shi, Japan, both corporations of Japan No Drawing. Filed Nov. 19, 1963, Ser. No. 324,867 Claims priority, application Japan, July 19, 1963, 38/ 36,781 7 Claims. (Cl. 117-4) The present invention relates to a method for avoiding intertwinement in carding staple fibers composed wholly or partially of polypropylene staple fibers by modifying the surface of such fibers before the carding operation.

Polypropylene fiber is liable to be intertwined in the card clothing during the carding stage of the spinning process due to the low melting point of polypropylene fiber and its peculiar surface characteristics. Accordingly it is difiicult to obtain high quality web from fibers containing a major proportion of polypropylene since the quality of the carded web directly affects the quality of the sliver produced therefrom, as well as causing diificulties in other subsequent stages of the spinning operation, the final spinning yarns containing polypropylene fibers are generally unsatisfactory.

Various expedients, including modification of the carding machines and reducing the number of physical treatments, have been proposed to minimize this intertwining of polypropylene fibers.

It is the present practice to produce barely acceptable web by limiting the above operation and the fineness of fiber to a specified range and adapting a large gauge rate for card settings. The yarns spun from sliver made of the inferior web as described, cause the disorderly spinning operation due to the poor intertwinement of the fibers. It is needless to say that the fiber product which is made by the above-mentioned operations has the unsatisfactory property. The surface property of the polypropylene fiber is different from the other types of fibers, as the above mentioned. It has a great tendency to intertwine in the card clothing during carding operation. The solution is considered to be the important problem in manufacturing spinning yarns as well as polypropylene fiber.

The object of the present invention is to provide a method for manufacturing a satisfactory web by modifying the surface property of polypropylene fiber and protecting polypropylene fiber from intertwining in the card clothing during the carding operation.

To achieve the above stated object, the present invention provides for treating polypropylene fibers with an organic phosphate prior to the beating operation so as to change the surface property of the polypropylene fiber. Thus it enables to prevent polypropylene fiber from intertwining in the card clothing. It is necessary to treat beaten fiber by the carding machine in order to make web from fibers containing polypropylene fiber. Among the carding machines, there are fiat card and metallic card of cotton spinning system, roller card of worsted system, roller card of woolen system, and condensing card of Bourrette spining system.

The fibers used for the present invention are polypropylene fiber, or mixed polypropylene fiber with natural fibers, artificial fibers or synthetic fibers. But polypropylene fiber is considered to cause essentially intertwining in the card clothing during the carding operation. It shows a tendency of observing the said results when the mixing rate of polypropylene fiber is more than 20%.

When polypropylene fiber and other fibers are mixed, it is acceptable to conduct previously polypropylene fiber treatment specified in the invention. Then the mixing operation is followed.

The fibers to be mixed with polypropylene fiber should be selected according to the types of spinning web desired.

If the surface treatment of polypropylene fiber is conducted according to the procedures requested by the present invention during spinning operation, it causes the ineffective result at the subsequent scouring process. For this reason, the surface treatment should be performed after the scouring process is completed. Therefore it is acceptable to perform this treatment at the tow condition after the spun tow is scoured and it may also be done after the staple is cut off. The scouring should not follow the treatment until the carding operation is completed.

The surface treatment method of polypropylene fiber demanded by the present invention is to adhere organic phosphate on polypropylene fiber surface. Polypropylene fiber is submerged in the solution which contains the said compounds, removed therefrom and then dried by centrifuging or. other suitable methods. If desired the solution may be sprayed on the fibers instead of immersing the fibers in a body of the solution.

The treatment agents specified in the present invention are essentially containing organic phosphate which is expressed by the undermentioned general formula. In addition to this, the treatment agents contain aqueous solution mixed with the proper amount of the other surfactants and lubricants.

Organic phosphate specified in the present invention is alkyl phosphate or alkyl-aryl phosphate. The general formula is expressed as follows:

Monooctyl phosphate Dioctyl phosphate Monodecyl phosphate Didecyl phosphate Monolauryl phosphate Dilauryl phosphate Monomyristil phosphate Dimyristil phosphate Monocetyl phosphate Dicetyl phosphate Monostearyl phosphate Distear'yl phosphate Monooctyl phenyl phosphate Dioctyl phenyl phosphate Organic phosphate required for polypropylene fiber surface treatment should be the sufiicient amount so that polypropylene fiber surface can be essentially denatured. It is expected to obtain the satisfactory result by using about 0.1% by weight of polypropylene fiber. The denaturation effect on polypropylene fiber surface is reduced when the amount of organic phosphate is less than 0.01%. It may hardly expect any effect at 0.005% or less. Even if the large amount of organic phosphate is used, it is not involved with any difiiculty if the treatment solution is miantained to pH value of about 6-8. But it may result in the costly treatment. a

Organic phosphate mixed with the other surfactants and lubricants can be used as the treatment solution. The surfactants and lubricants are as follows:

Anion surface active agents such as: alkyl sulfate, alkyl sulfonate, alkyl aryl sulfonate, alkyl succinate, alkyl amide alkyl carboxylate and alkyl amide alkyl sulfonate. Nonionic surface active agents and amphoteric surface active agents such as: polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkyl aryl ether, polyoxyethylene alkyl amine and fatty acid diethanol amide. Lubricating constituents such as: mineral oil, vegetable oil, fatty acid monoglyceride, glyceride of lower fatty acid and higher fatty acid. Although there is no special limitation for the mixing rate of those surfactants and lubricants, it is desired to mix them so as to provide the effective action of organic phosphate. If the amount of agents other than organic phosphate is proportioned more than times of organic phosphate, it shows a tendency of losing the property of organic phosphate by the action of the other oil agents. It is desired to maintain the amount of other agents within two times of the quantity of organic phosphate. Even if they are forming the mixed micelle, it is desired to adhere to polypropylene fiber without encountering with any difficulty.

The treatment agents used for this invention are able to adhere to polypropylene fiber after dilution. For a low concentration a large amount of treatment solution should be used to insure adherence of sufficient agent. With a high concentration it is difficult to control the treatment. The treatment agents should be diluted to 0.1%5% preferably about 1% concentration.

Thus it is desired to maintain the diluted solution to range pH value of 6-9.

The efiect of organic phosphate on polypropylene fiber is entirely difierent from the general spinning lubricant. This is demonstrated by the results of the following tests:

( l SAMPLE-STAPLE Staple A: Isotactie polypropylene, which has intrinsic viscosity 1.47 (measured in Tetralin at 135 C.), is melted at 260 C. and spinned by the ordinary method. They are stretched to 4.73 times as they are steam heated at 98 C. Then they are cut off after crimped (l2 crirnps per mm.). Fineness 1.5 denier. Staple length 38 mm.

Staple B: The above sample Staple A is steam heated at 130 C. for minutes.

(2) TREATMENT Adhered amount- Percent Staple A 0.25 Staple B 0.27

(2) Sodium lauryl sulfate.

Adhered amount- Percent Staple A 0.27 Staple B 0.27

(3) Spinning oil commercially available 1: Mainly composed of sulfonated sperm alcohol.

Adhered amount Percent Staple A 0.26 Staple B 0.25

(4) Spinning oil commercially available 2: Mainly composed of fatty acid ester of polyhydric alcohol.

4 Adhered amount- Percent Staple A 0.25 Staple B 0.22

(5) Spinning oil commercially available 3: Mixture of mineral oil, vegetable oil, and surface active agent.

Adhered amount Percent Staple A 0.26 Staple B 0.25

(6) Spinning oil available commercially 4.

Sodium sulfonated sperm alcohol Glycerol monostearate 20 Sodium salt of dilauryl sulfosuccinate 10 Adhered amount- Percent Staple A 0.26 Staple B 0.25

(7) Spinning oil commercially available 5.

Pentaerythritol monostearate Sodium sulfonated sperm alcohol 20 Adhered amount- Percent Staple A- 0.25 Staple B 0.22

(8) Spinning oil commercially available 6.

Mineral oil 50 Methyl oleate 20 Pentaethylene glycol (5 mol) oleyl ether 30 Adhered amount Percent Staple A 0.26 Staple B 0.25

(9) Mixture of (l) and (3) agents as the effective constituents.

Mixing ratio 1:1

Adhered amount Percent Staple A 0.25 Staple B 0.27

(3) CARD TEST TABLE 1.-RESULTS OF CARD TEST Passing rate of Passing rate of Staple A (percent) Staple B (percent) 9io00 91000 M000 M000 M000 91000 Treatment Agent No.:

Gage setting (in.)

No web formation due to static electrleity 96. 7 96.9 96. 9 95. 9 96. 5 96. 9

Friction coefiicient: The friction coefficient of fibers are measured according to the method described in the articles by H. L. Roder, Journal of the Textile Institute, 44, 247-265 (1953).

TABLE 2.-FRICTION COEFFICIENT Type of Fibers Material A 7 Material B Static Dynamic Static Dynamic Coeflicient of Fric- Friction Friction Friction Friction tron Coefl. Coefi. Coefi. Coefi. Treatment Agent N 0.:

As noted in Table 1, staples A and B show the satisfactory passing performance for the treatment agent 1 and 9 in spite of using small gage ratings. However, agents 3, 4, 5, 6, 7 and 8 show the considerable intertwinement and indicate'the poor passing rate. Specially it is observed that staple B gives entirely unacceptable results for the narrow gage rating. From Table 2, agents 1 and 9 indicate lower fiber friction rating than agents 2, 3, 4, 5, 6, 7 and 8 and represent the excellent smoothness. It is considered to provide the desirable results.

The reasons of intertwining polypropylene fiber in the card clothing during the card operation and causing the spinning difficulty are not known. It has been suggested that it may be due to physical properties inherent in the internal structure of polypropylene fiber, as well as an adhesive property of non-crystalline polypropylene polymer on the surface of the fiber. Another possible explanation is the high coefficient of friction which is considerably higher than that of other synthetic fibers.

Organic phosphate forms a strong bond on the surface of the polypropylene fibers treated in accordance with the invention, with substantial modification in the properties. The surface now has lower frictional characteristics and there is less tendency to adhere between fibers. In any event, regardless of the theoretical explanation, the thus-treated polypropylene fibers are amenable to carding without intertwinement, thereby efiiciently producing fine grade web.

Example 1 1000 kg. of polypropylene staple, fineness 1.5 denier, staple length 38 mm. previously stretched, treated with steam, and cut off by the conventional method, are dipped into 1% solution of potassium salt of cetyl alcohol ester phosphate (diester about 60%, others mainly monoester, 1% aqueous solution pH 7.3). The moisture content is reduced to 20% in a centrifugal separator and dried in a drier. They are moisture conditioned for 24 hours after this drying and made into lap by the beater and then made into sliver by the fiat card of the cotton spinning system.

As a result, there was observed almost no intertwining in the taker-in-roller and cylinder. Uniform high grade Web and even slivers were produced containing a very small amount of neps. There was scarcely any fly observed and a passing percentage of 98.2% was obtained.

However, sodium octyl phosphate is composed of 50% of diester and the remaining is mainly monoester. It is 1% solution of pH 6.8 value. Spindle oil is viscosity of 55 sec. (30 C. Redwood see), flash point 155 C.

The above treatment agent was processed to 20% emulsion. Polypropylene staple was spun and stretched, steam heated and cut off to 2 denier, 59 mm. by the conventional method, and then sprayed with the above emulsion amounting to 0.45% of the weight of the fiber. After moisture conditioning for two days, card webs were made by the roller card of the worsted system.

As a result, it was observed no intertwining in the roller card. The high grade web and the uniform fine quality top were produced. A mixture of 40% of this top and 60% wool top Was spun by the French system.

Test results of gilling: During the gilling operation, static electricity was not generated and noils were scarcely noticeable. Small amounts of neps were observed. The drawing operation was performed satisfactorily.

Test results of roving operation: Upon drawing on the reducer machine, there was obtained a uniform roving sliver which was satisfactorily drawn on the finisher machine. There was no noticeable intertwining at the rubber roller and a uniformly fine roving was produced with no apparent cut-off.

Test results of ring spinning frame: Scarcely any thread cuts, neps or fuzzing was noticed, and the yarns obtained were of fine quality.

We claim:

1. A process for manufacturing web comprising polypropylene staple fibers comprising:

(a) treating polypropylene staple fibers with an aqueous liquid vehicle containing at least 0.01% by weight of an organic phosphate having the general formula:

wherein at least one of R R and R is selected from the group consisting of alkyl or alkyl-aryl having from 8 to 18 carbon atoms and the remainder of R R and R are selected from the group consisting of hydrogen and alkali metals;

(b) removing liquid vehicle from the thus-treated staple fibers with retention of said phosphate on said fibers;

(c) beating the phosphate treated fibers; and

(d) carding the beaten fibers to form a web thereof substantially free of intertwining.

2. A process as set forth in claim 1, wherein the amount of phosphate in the treating vehicle is about 0.1-5

3. A process as set forth in claim 2, wherein the liquid vehicle contains also a lubricant for polypropylene fibers.

4. A process as set forth in claim 2 wherein the phosphate is sodium lauryl phosphate.

5. A process as set forth in claim 2 wherein the phosphate is cetyl alcohol ester phosphate.

6. A process as set forth in claim 2 wherein the phosphate is sodium octyl phosphate.

7. A process for preparing polypropylene staple fibers having substantially no tendency for intertwinement during carding thereof which comprises wetting a tow of polypropylene fibers with an aqueous solution containing from 0.1 to 5% of an organic phosphate having the formula:

wherein at least one of R R and R is selected from the group consisting of alkyl or alkyl-aryl having from 8 to 18 carbon atoms and the remainder of R R and R are selected from the group consisting of hydrogen and alkali metals, drying the wetted tow with retention of the said organic phosphate on the fibers thereof, and cutting the thus-treated tow to form polypropylene staple fibers for further processing into threads and yarns.

3,224,889 12/1965 Schulde 117-139.5 3,099,515 7/1963 Goodings et a1. 117-138.8 X 3,145,073 8/1964 Gagliardi 8-55 X References Cited UNITED STATES PATENTS I r OTHER REFERENCES Gefter, E. L.: Organophosphorous Monomers and Mims Polymers, Associated Technical Services, Inc., Glen Kern 1985 Ridge, N1, 1962 (pages XXIII relied on). Billings 1l7139.5 X Mat hews 1171 9 10 WILLIAM D. MARTIN, Primary Examiner. Brunt et a1 117-1395 Wishman et a1 117*1395 X R. HUSACK, Asszszant Exammer. 

1. A PROCESS FOR MANUFACTURING WEB COMPRISING POLYPROPYLENE STAPLE FIBERS COMPRISING: (A) TREATING POLYPROPYLENE STAPLE FIBERS WITH AN AQUEOUS LIQUID VEHICLE CONTAINING AT LEAST 0.01% BY WEIGHT OF AN ORGANIC PHOSPHATE HAVING THE GENERAL FORMULA: 